Re: C++ ABI: Mangling of call_expr

[Mark Mitchell <mark at codesourcery dot com>]

On Tue, 2003-06-24 at 03:32, Nathan Sidwell wrote:
> Giovanni Bajo wrote:
> > Hello,
> > 
> > I can't understand how mangle.c is supposed to mangle a call expression.
> > Currently, it just segfaults on it. The expression production from the ABI
> > says:
> > 
> > <expression> ::= <unary operator-name> <expression>
> >             ::= <binary operator-name> <expression> <expression>
> >             ::= <trinary operator-name> <expression> <expression>
> > <expression>
> > [...]
> > 
> > But what is a CALL_EXPR? Its two-letter mangled name is "cl", but it
> > certainly can't be either unary, binary, or trinary. In fact, in
> > operators.def, it is defined with arity "-1", which means "any arity is
> > allowed". But then, I can't see which production is supposed to use.
> looks like a bug in the ABI spec. To be demanglable, there must be a count
> of the number of parameters encoded.
> 
> Mark, have I missed something?

Only that this is a known issue, with no known solution.

Steve Adamczyk and I agreed at one point that the ISO C++ standard
allows far too much complexity in expressions in this context:

  S<sizeof (new (p) X(3.2, a->b (c)))>

is pretty goofy.  

However, the standard does presently seem to allow that.

I was pretty sure I had raised this issue on the ABI mailing list, but I
don't see that message, so maybe I never did.

-- 
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com